A 40-year-old woman who experienced progressive right abdominal pain for 1 month was admitted to our hospital. The patient and her family members were diagnosed with Carney complex (CNC). Two years prior to admission, the patient underwent percutaneous needle biopsy of a newly diagnosed intercostal mass near segment V of the liver by computed tomography (CT) (Fig. 1A) and biopsy suggested the presence of psammomatous melanotic schwannoma (PMS). At admission, CT images showed a 3.9 × 1.5 cm mass with ill-defined (Fig. 1B). The size of the mass increased by 1.9 cm in 2 years, and newly occurring calcification was present. Laparoscopic tumor resection was performed. The tumor biopsy revealed a distinct transition between the hypercellular epithelioid central and hypocellular spindle peripheral zones (Fig. 1C), together with the melanin-containing spindle cells and psammoma bodies, stained positively for HMB45 (Fig. 1D). Based on positive staining for S-100 protein (Fig. 1E), and vimentin, the tumor was diagnosed as a malignant PMS. The 2-[fluorine-18]-fluoro-2-deoxy-D-glu-cose-positon emission tomography/CT (FDG-PET/CT) performed at the initial diagnosis of PMS, showed no significant FDG uptake (Fig. 2A); however, at admission, intense FDG uptake in the intercostal mass was observed (Fig. 2B). Approximately 3 years after the diagnosis of PMS, the patient suffered from tumor growth and distant metastasis (Fig. 2C-2G), and died despite adjuvant chemotherapy and radiotherapy.

The PMS tumors has been described in isolated cases or, more frequently, in cases of CNC. Although malignant PMS of the spine has been described in patients with CNC, malignant intercostal PMS in CNC has not been reported in the literature to date, to the best our knowledge. Based on our case, we suggest that early complete resection of PMS and rigorous follow-up are necessary for patients with CNC due to the risk of malignant transformation.